In a C-arm system, the three-dimensional field of view is limited by the geometrical arrangement of the distance between source and detector and the detector size itself. For imaging procedures on a C-arm system providing tomographic X-ray image data, which procedures are also referred to as CT-like imaging procedures, this limitation is of disadvantage when the area of interest is not completely covered by the three-dimensional field of view. For example, in operational interventions in relation with the liver, for example in hypervascular liver lesion treatment, the region of interest may not be fully covered by the three-dimensional field of view. US 2011/0255657 A1 relates to CT image acquisition and describes the lateral displacement of a detector to increase the 3D field of view. However, the detector has to be provided to be shiftable, requiring mechanical means to allow the displacement.